透過您的圖書館登入
IP:18.206.12.31
  • 學位論文

臺灣東北部蕨類與石松植物之物種組成與蕨類群集之葉部形態形質沿海拔梯度之變化

The pattern of fern and lycophyte species composition and community-level fern leaf functional traits along an elevation gradient in Northeastern Taiwan

指導教授 : 澤大衛

摘要


被子植物之葉部形態形質往往隨環境因子而改變,顯示其適應不同棲地環境的生長機制。蕨類植物在植株型態與生活史上與被子植物有明顯的差異。但有關於蕨類之葉部形態形質以及其生長機制如何隨環境梯度而改變的研究卻十分少見,且臺灣亦少有沿環境梯度設立樣區調查蕨類群集的研究。本研究旨在了解1)蕨類與石松之物種組如何隨環境因子而改變、2)蕨類物種間葉部形態形質之差異與其葉片生長機制之間的關係,以及3)蕨類群集之葉部形態形質如何隨環境因子而改變。臺灣是一個具有明顯海拔差異的島嶼,許多環境因子也同時隨著海拔而改變,造就了多樣的棲地。為了解海拔與其他環境因子如何影響蕨類與石松植物,我在臺灣東北部海拔850公尺至2100公尺間之山區設立了18個20×20公尺及60個10×10公尺之樣區,紀錄各樣區之微氣候、地形、土壤、光照,及生物性環境因子。同時,調查了地生與附生蕨類之物種組成,並採集葉片樣本進行一系列之形質特徵測量,包含葉厚、葉面積、比葉面積(specific leaf area, SLA)、單位面積之葉綠素含量、葉乾物質含量(leaf dry matter content, LDMC)、葉肉質程度(succulence)、總碳與總氮含量、13C/12C 比例,以及15N/14N比例。在統計分析上,物種組成與環境因子間的關係由除趨勢對應分析(detrended correspondence analysis, DCA)和典範對應分析(canonical correspondence analysis, CCA)來檢測;形質特徵與形質特徵間的關係由皮爾森相關性檢定分析(Pearson’s correlation test)以及主成分分析(Principal component analysis)來檢測;族群之形態形質與環境梯度之關係由RLQ分析與第四角分析(fourth-corner analysis)來檢測。結果顯示,所有樣區總計有121種蕨類與石松植物,其中83種蕨類經過形質特徵之測量與分析,48種為地生,35種為附生。在物種組成方面,地生與附生之物種主要皆隨海拔與溫度而改變,地生物種還受土壤酸鹼度和坡度影響,而附生物種則亦受土壤碳氮比(間接地)及林冠與地形之開闊度影響。地生物種中,於較低溫或有較高酸度土壤之棲地主要可見瘤足蕨屬物種分布,於較溫暖之棲地則主要為雙蓋蕨屬植物;數個物種如紅苞蹄蓋蕨及雉尾烏毛蕨於陡坡之環境中常見。附生物種中,於溫暖之棲地主要可見兩種巢蕨及半附生之瓶蕨、波氏星蕨;在主要由巨大檜木組成之高土壤碳氮比棲地中,膜蕨科物種為優勢;兩種具有硬葉之水龍骨科蕨類及兩種膜蕨屬物種在樹冠與地形開闊向陽之環境中為優勢。經歸納,地生蕨類物種之葉片有三種主要的生長策略,分別為1)速生型(acquisitive)、2)精緻慢生型(delicate conservative)、3)抗逆境慢生型(resistance conservative);附生蕨類的葉片主要可歸納為四種生長機制,分別為1)速生缺水落葉型(acquisitive drought-deciduous)、2)半耐旱型(intermediate)、3)耐旱保守型(xeromorphic conservative)、4)脫水復原型(poikilohydric)。地生物種之生長機制差異主要源於葉乾物質含量隨低溫逆境與低土壤養分可得性的環境而改變,而附生物種的生長機制差異主要是由於葉肉質程度與葉面積隨乾旱逆境與光照強度的改變所致。

並列摘要


Leaf morphological traits of angiosperm species are often related to environmental factors, revealing distinct strategies of plants adapting to different habitats. Ferns have distinct growth form and life history comparing with angiosperms, though few studies have focused on how ferns’ leaf morphological traits and growing strategies change along environmental gradients, and in Taiwan there are also few research have studied on how fern species composition change along environmental gradients based on plots survey. This study aims to understand 1) how do fern and lycophyte species composition change along environmental gradients; 2) how do the trait differences between fern species relate to their leaf growing strategies, and 3) how are the relationships of community-level fern’s leaf morphological traits and environmental factors. Taiwan has strong elevation gradient, driving the change of many environmental factors and creating diverse habitats. To find out how does elevation and other environmental factors affect ferns and lycophytes, I established 18 20×20-m plots and 60 10×10-m plots at elevation zones between 850 and 2100 m a.s.l. in northeastern Taiwan, and recorded microclimatic, topographical, soil, light, and biotic environmental factors. Terrestrial and epiphytic fern species composition were surveyed, and leaf sample were collected and measured for a set of traits including leaf thickness, leaf area, specific leaf area, area-based chlorophyll content, leaf dry matter content, succulence, leaf total carbon and nitrogen content, 13C/12C ratio, and 15N/14N ratio. In statistical analysis, species-environment relationships were analyzed by detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA), trait-trait relationships were analyzed by Pearson’s correlation test and display by principal component analysis, response of community-level traits along environmental variables were analyzed using the RLQ and fourth-corner methods. Overall, I found 121 fern and lycophyte species, 83 ferns have been measured and analyzed, 48 are terrestrial and 35 are epiphytic. Both terrestrial and epiphytic species composition mainly changed with elevation and temperature, while terrestrial species’ composition also changed with soil pH and slope, epiphytic species’ composition also changed with soil C:N ratio (indirectly) and site openness. In terrestrial species, Plagiogyria species had optima at mid to low temperature or more acid soil habitats; Dipluzium species had optima at warm habitat; several species such as Athyrium nakanoi, Blechnum melanopus had optima at steep habitat. For epiphytic species, two nest ferns and two hemiepiphytic fern had optima at high temperature habitat; Hymenophylaceae species had optima at high soil C:N ratio habitat which dominated by large Chamaecyparis tree; two hard leaf Polypodiaceae species and two Hymenophyllum species had optima at high site openness habitat. Three growing strategies are identified for terrestrial species, including 1) acquisitive, 2) delicate conservative, and 3) resistance conservative; four strategies are identified for epiphyte: 1) acquisitive drought-deciduous, 2) intermediate, 3) xeromorphic conservative, and 4) poikilohydric. Terrestrial species’ growing strategies were mainly related to the change of LDMC to the stress of cold and low nutrient availability, epiphytic species’ strategies were mainly related to the change of succulence and LA to the drought stress and light intensity.

參考文獻


1. Acebey, A. R., Krömer, T., & Kessler, M. 2017. Species richness and vertical distribution of ferns and lycophytes along an elevational gradient in Los Tuxtlas, Veracruz, Mexico. Flora 235 83–91.
2. Becker, R. A., Wilks, A. R., Brownrigg, R., Minka, T. P. & Deckmyn, A. 2018. maps: Draw Geographical Maps. R package version 3.3.0. https://CRAN.R-project.org/package=maps
3. Becker, R. A., Wilks, A. R. & Brownrigg, R. 2018. mapdata: Extra Map Databases. R package version 2.3.0. https://CRAN.R-project.org/package=mapdata
4. Benzing, D.H. 1990. ‘Vascular epiphytes. General biology and related biota.’ Cambridge University Press: Cambridge
5. Bivand, R. & Lewin-Koh, N. 2019. maptools: Tools for Handling Spatial Objects. R package version 0.9–5. https://CRAN.R-project.org/package=maptools

延伸閱讀